Efforts to extend Moore's law for integrated circuitry (IC) have included development of transistors employing materials other than silicon, such as III-V compound semiconductor materials (e.g., InP, InGaAs, InAs). These non-silicon material systems typically display higher carrier mobility than silicon devices, and so their introduction has long been suggested as path toward faster transistors. However, along with higher carrier mobility, in a field effect transistor (FET) the off-state (Ioff) leakage between source and drain can be significantly higher for III-V (and Ge) channeled device than for a silicon-based FET of equal effective (electrical) channel length. As off-state leakage is generally an exponential function of effective channel length, it may be unclear how transistor density, rather than transistor speed, might be improved through the use of high-mobility semiconductor materials.